1. Technical Field
The present invention relates to an oscillator, an electronic apparatus, and a moving object.
2. Related Art
A crystal oscillator which is used for a reference frequency signal source of a communication apparatus or a measurement apparatus is required to be stable in output frequency with high accuracy with respect to a temperature change. In general, an oven controlled crystal oscillator (OCXO) is known as a crystal oscillator which obtains extremely high frequency stability. Furthermore, recently, characteristics of a temperature compensated crystal oscillator (TCXO) have improved dramatically, and have been developed to the extent of approaching the frequency accuracy or frequency stability of the OCXO.
An oscillator with such a high accuracy is used for, for example, abase station or the like for mobile phones, and an oscillator which can control a frequency using a digital control may be required. JP-A-2011-101212 discloses a piezoelectric oscillator which includes a D/A converter, a vibrator, and an oscillation loop circuit, and varies a frequency of a signal that is output from an oscillator by changing an input signal with respect to the D/A converter.
However, if it is assumed that a control of varying a frequency and temperature characteristic compensation of a frequency are simultaneously performed, it is necessary to add the amount of temperature correction to a bit value of a digital input signal, a select range of a bit value which can be used as a frequency variable voltage is narrowed, and thus, there is a problem in which a frequency control range is narrowed.